Fix regression with saveSelection
Add drag support for images

Works only with browsers which support caretRangeFromPoint. The feature
is disabled for other browsers.
Don't adjust the content sizes on value changes

I spend half an hour to figure out why style="width: auto; height:
auto;" were add to my images. This should be done when the images are
inserted.
Use the native scroller instead of SC.ScrollView

This commit also remove the repaint hack (since it's not require
anymore) and remove some useless code.
Revert "Use the native scroller instead of SC.ScrollView"

This reverts commit 472fc25bebbc3f39ef657114fd82d787aff7a8e0.
Code refactoring
Drag image on mouseDragged and not on mouseDown

Also add some documentation.
this.resignFirstResponder on blur
Some fixes
Fixes again
Responder fix
updateState on notifyDomValueChange instead of on invokeCommand
Fix an issue with insertNewline and deleteBackward and add a defaultValue property
Some documentation
Add command factory documentation
Add undo/redo management
Call notifyDomValueChange after a drag
Hack to get the correct height after a drag
Add features to README
Add an option to paste as plain text

Also copy some properties from SC.WYSIWYGEditorView to SC.WYSIWYGView